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Iditarod: Celebrating the “Great Race of Mercy” to Stop Diphtheria Outbreak in Alaska

Today's Vaccines Recommended across the Lifespan

DTaP vaccine: for infants and children

Tdap vaccine: for preteens, teens and adults

Td: for teens and adults who've already received Tdap

Upper-case letters in these abbreviations denote full-strength doses of diphtheria (D) and tetanus (T) toxoids and pertussis (P) vaccine. Lower-case 'd' and 'p' denote reduced doses of diphtheria and pertussis used in the adolescent/adult-formulations. The 'a' in DTaP and Tdap stands for 'acellular,' meaning that the pertussis component contains only a part of the pertussis organism.

Years ago, diphtheria wiped out entire communities, sometimes killing all the children in a family. This is the story of a famous event that galvanized people in the United States to begin to use diphtheria vaccine—which has virtually wiped out the once dreaded disease in this country.

A Deadly Outbreak

In the winter of 1925, a lone physician and four nurses in Nome, Alaska faced a crisis too terrible to imagine—an outbreak of diphtheria that could kill most of the region's population of about 10,000 people.

Diphtheria is a highly contagious upper respiratory tract illness caused by the toxin-producing bacterium Corynebacterium diphtheriea. The disease can be treated with an antitoxin (serum containing antibody to neutralize the toxin) or prevented by vaccines (e.g., DTaP, Tdap or Td – “D/d” for diphtheria, “T” for tetanus, and “P/p” for pertussis). However, before these medicines were available, diphtheria was commonly known as the “strangling angel of children.” Diphtheria causes the throat to become blocked with a thick, leathery coating that makes breathing very difficult. Without treatment, death by suffocation is very likely, especially for young children.

In December 1924, Nome doctor Curtis Welch watched as an outbreak started—with cases first thought to be simple sore throats or tonsillitis. In January 1925, when 2 children died of diphtheria, the impending crisis became clear. Dr. Welch ordered a quarantine, but diphtheria is so contagious that many people were likely already exposed and he knew more cases would appear.

Race dogs with shirts promoting immunization during the ceremonial beginning of the Iditarod race. Photo courtesy Doreen Stangel, State of Alaska Immunization Program.

Help from Miles Away

Normally, Dr. Welch would have treated infected people with diphtheria antitoxin to fight off the effects of the poison that diphtheria releases into the body. But the town’s supply of antitoxin was not enough and it had expired. Not knowing if the expired antitoxin would work or if it might actually cause harm, Dr. Welch hesitated to use it.

To save lives, fresh diphtheria antitoxin was the only hope. On January 22, 1925, Dr. Welch sent dozens of telegrams pleading for help to find and deliver antitoxin. National leaders in Washington, D.C., helped to locate the closest large supply of diphtheria antitoxin—it was in Anchorage, hundreds of miles away.

The next problem—figuring out the fastest way get the antitoxin to Nome. There were no roads or railways to Nome, air service was unavailable, and ships could not reach the town because of sea ice around Nome. The only way in was overland via the Iditarod Trail, also known as the Seward-to-Nome Mail Trail. This crisis made newspaper and radio headlines across America.